1. Field of the Invention
The present invention relates generally to a method of supplying a replenishing solution in an automatic developing machine, and more particularly to a method of supplying a replenishing solution in an automatic developing machine in which the deterioration of a developer due to air is compensated for.
2. Description of the Prior Art
A lithographic developer, for example, may be used in obtaining high-contrast development of a photosensitive material. Typically, the lithographic developer contains only hydroquinone as a developing agent thereof. In order not to preclude or damage the capability of infectious development of the developer, sulfite as a preservative is used in the form of an addition product of formaldehyde therewith, and thus the concentration of free sulfurous acid ions is extremely reduced. Therefore, such a lithographic developer is remarkably susceptible to oxidization due to air, and has a material disadvantage in that it cannot possibly be preserved for greater than three days.
It is known that a hydrazine derivative is commonly employed in a method using a stable developer which is not susceptible to oxidization due to air. In accordance with the method, since highly concentrated sulfite may be added to a developer, the stability of the developer with respect to oxidization due to air is drastically improved. In the method using a hydrazine derivative, however, the pH of the developer is set to a value higher than the pH of a normal lithographic developer, so that the pH value tends to easily vary. This gives rise to a problem in that results derived from photographic characteristics are prone to vary due to the variations in the pH value.
On the other hand, attempts at stabilizing a developer have heretofore been made by improving a method of supplying the developer in an automatic developing machine. However, any proposal concerning an improvement in the supplying method is confined solely to the case of a lithographic developer. For this reason, any of the prior-art proposals gives consideration to deterioration factors such as aging fatigue (deterioration derived from oxidization) and processing fatigue (deterioration derived from development) in connection with a method of supplying the lithographic developer. However, no satisfactory proposal has been made with respect to a method in which silver halide photographic material containing a hydrazine derivative is processed and utilized in a stable state over an extended period of time by means of an automatic developing machine.
For instance, when using a high-contrast type developer including hydrazine by which a value of film is equal to or greater than 10, the activity of the developer in aqueous form is increased by its oxidization due to air. Thus, the sensitivity is increased and black spots on film are produced. To prevent this phenomenon, in the case of automatic development, the activity of a replenishing solution employed is typically adjusted to a lower level than that of a development initiating solution used therewith. However, as the quantity of a photosensitive material processed per unit time is increased, the quantity of a less-active replenishing solution to be supplied must be increased accordingly. This leads to the disadvantage that the thus-obtained activity of the solution is progressively decreased.